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Difficult to calculate a tree’s actual value, but there is a method

JOHN DeGROOT, Special to The Observer

Friday, February 26, 2016
9:21:06 EST AM

A sycamore tree on the Lakeshore Road boulevard near Christina Street. Gardening expert John DeGroot says it’s difficult to provide a monetary value for a tree, although there are some formulas that have been used. He suggests that some of the benefits provided by trees can’t be measured by dollars and cents and that these benefits really are priceless. (John DeGroot photo)

The Internet is a wonderful source of information, some accurate and some not so.

A week or so ago, someone sent me information on the value of trees. Since I am a tree nut of sorts, I thought I better read on. According to a Professor T M Das, of the University of Calcutta, a 50-year-old tree had a calculated value of $193,000. The backup calculation listed the value of oxygen generated from a 50-year-old tree to be $31,250. The value of pollution control was $62,000. The increase in value of soil fertility and soil erosion was $31,250, the value of recycled water was $37,500 and the tree provided $31,250 of value to birds and other animals. All in American funds I assume.

The sceptic in me wonders how someone could accurately compute these figures. I continue with my scepticism by wondering why three of T M Das’s numbers coincidentally landed on $32,500. I might go on to question if there really was a person by the name of T M Das.

But the point has been made and has been well taken. Trees do indeed have tree-mendous value that we readily take for granted.

I am often called upon to put a monetary value on a tree that has been destroyed by accident, fire or other unfortunate circumstance. If the damaged tree is small, it is easy to arrive at a value to plant a replacement tree. But if the tree is mature and too large to transplant, I rely on a formula that I picked up from my university days, and is still the standard today. This formula takes the following four factors into consideration: size, location, species and condition.

For size, the easiest factor to consider, I measure the diameter of the tree at breast height, apply a cost, and arrive at a number which is usually shockingly high.

Step two considers the tree’s location. A tree that is planted in the centre of the front lawn at a city hall has more value than a similarly-sized tree found in the middle of a dense bush.

Next, we look at a tree’s condition or health. A tree that is in good health and shows no signs of stress will have a higher value than a tree that has been hit by lightning or has a disease or pest problem such as emerald ash borer.

The final factor to be considered is the tree’s species. A native Canadian beech, pine or oak will have a higher value than a less desirable imported willow or poplar.

Plug all these numbers into a formula, and we arrive at a reasonable value for appraisal purposes, likely a fraction of Professor Das’s calculation.

Some might argue that trees have a higher value than Das has calculated. Studies have shown that hospitalized patients whose windows overlook a parking lot will not recover as quickly as those who overlook a wooded forest.

There’s also much value in a simple walk in the woods. And the value of a kid’s tree fort or of a tire swing hung from a long rope giving benefit to those who relaxingly use it. Difficult to put a value on but priceless, nonetheless.